Process for producing solid castings and their products.



J. B. WALKER.

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7 APPLICATION HLED JAN. 22. 1918. Q 1,294,209. Patented Feb..11,1919.

14 wwww o1 Mall/V B. WALKER wall so as to permit the gases trapped there' JOHN B. WALKER, OE B IRMINGHAM ALABAMA.

Y PROCESS FOR PRODUCING SOLID CASTINGS AND THEIR PRODU CTS.

To all whom it ma concern:

Be it known t at I, JOHN B. WALKER, a citizen of the United States of America, residing at Birmingham, in the county of Jefferson and State of Alabama, have invented certain new and useful Improvements in Processes for Producing Solid Castings and Their Products, of which the following is a specification.

My invention relates to a new and improved method of casting ingots and castings so asto reduceto a minimum the defects in the body of the casting due to gas pockets, piping and the like wh1ch may generally be said to result from the chilling and hardening of the outer walls of the casting while its core and center is still molten so that the gases generated in the casting become trapped to form therein gas pockets and the molten core as it chills and contracts shrinks away from the casting walls and leaves a large pipe or cavity.

My process, in its broadest sense, contemplates the removal of the gases from within the casting during the period it is solidifying by means of an artificial vent or flue which penetrates the castings frozen outer in to escape freely from the hot center of the casting as it gradually cools. I cause this vent, when formed by an inserted flue, to extend sufiiciently below the frozen top or outer wall of the ingot or casting to exhaust the gases, the depth of penetration of the flue being empirically determined with due regard to the size of the casting and the character of the metal. Such a vent flue is the simplest means to the ends I have in view and may be of any character which can be cheaply and readily introduced into the top of the ingot or into the head or gate of a casting before it chills and which will resist any tendency of heat of the casting to destroy its venting functions. I have also discovered that if certain materials such as limestone, fluorspar, thermit and like reagents which have the effect of intensifying the heat and fluidity of the molten metal with which they are brought into contact, are introduced into the casting, they will cause an internal reaction which will vent the casting and raise its internal temperature to a point where the tendency to pipe i r ght under control and if this reac Specification of Letters Patent.

' Patented nee. i, rare.

Application filed January 22, 1918. Serial No. 218,138.

tion is used withthe artificial vent flue the piping may be practicallyeliminated.

In experiments which I have conducted with high carbon steel ingots I have caused the top of the in ct about the vent flue to collapse so that, t e ipe or shrinkage cavity was practically ellminated. A wide variety of reagents, the properties of which are well known to those skilled in this art, may

be employed to the ends above described and may be introduced in a very simple and practical manner by placing them in the lower closed end of a pipe or flue, the main portion of which may be left open or filled with material suitable for preserving the venting functions of the flue.

My invention further contemplates the reduction to a minimum of the metal in the heads of castings so that the maximum percentage of cast metal will be available for the production of finished products and to this end the venting flue is so introduced into the head that should the pipe occur in the casting it will be drawn up into the head and will leave the main body of the" casting solid. To illustrate this feature of my invention I have cast steel rolls weighing from. eight to twelve tons with heads reduced from three feet to less than two feet and have found the piping greatly re-- duced and wholly confined to the short head, the roll proper being entirely free from cavities or gas pockets.

The simplest and least expensive method of carrying out my invention is illustrated in the accompanying drawings, in which Figure 1 is a sectional view illustrating a high carbon steel ingot as produced by away to release the reagent and open the Fig. 4 illustrates another form of vented casting after treatment with my fluxing and ventin process.

Sim! ar reference numerals refer to similar parts throughout the drawings.

As illustrated, 1 is an ingot mold of any any other material which will not injuri-.

ously affect the ingot'or casti may be used. This pipe at its up erend as a handle 4 clamped thereto an at its lower endis pinched together at 5 so that it forms a container for a fillin if such is desired, of material which wil resist the heat of the casting1 so that it will not solldify and pre vent t e escape of gases through the pipe flue. This material should be such as not to injuriously afl'ect the ingot or casting when coming in contact with its molten metal. In practice, I have charged the pipe with lumps of slag or limestone and 'alumina, or dolomite, but any refractory materials, preferably such as will not take up carbon, ma be substituted. The handle 4 is so place as to come to rest on the mold 1 when the lower end of the pipe penetrates the desired distance into the casting.

It will at once be apparent that the cool wall of the pipe 3 will chill the casting metal about it and freeze the pipe or vent flue in osition with its lower end entering the mo ten interior of the casting. This end 5 will melt away leaving fixed in the upper end of the ingot a vent stack or open flue of material which will not conglomerate and through which the contained gases in the casting can escape and thus prevent gas pockets formin and reduce to a controlled minimum the piping loss in ingots. I have found that excellent results are obtained where a vent stack of four inch iron pipe is caused to penetrate a six ton steel ingot, about twelve inches as this will carry it well below the de th of. the frozen top zone of the ingot an it thus leaves the lower open end of the stack in communication with the slowly cooling molten center of the ingot where the generation of the gases is continuously proceeding as the ingot cools.

To obtain the best results from my process the vent pipe should be utilized as a preferred means to introduce into the casting a reagent or flux of such character as to intensify the internal heat of the casting about the base of the flue and increase the fluidity of the molten metal to facilitate the liberation of its gases. As shown in Fig. 2, I place at the lower end of the pipe 3 suflicient fluxing material 6 such as thermit, fluorspar, limestone. and the like which serves to so increase the internal temperature at the top of the in ot or casting as I in place in the castin sink down, as shown in Fig. 3, and contract, and in many cases fill, the pipe s acewith solid metal. of my invention, I inserted five pounds of thermit into a four. inch iron pipe and thrust it twelve inches into a large ingot.

As illustrative of t is phase The upper end of the ingot turned to a,

white heat and gases were driven off through the vent plpe for fifteen minutes.

In Fi 4 I show my invention applied to foun ry practice wherein a roll casting 7 is shown with the ten inches into its hea 8. A three and oneleaving the casting solid. have also thrust (pipe 3 inserted about my artificial vent flue into the gates of many large castings and freed them entirely from blow holes or gas pockets.

It is within the scope of my invention that the vent pipe may be used Without the reagent, and the reagent maybe introduced into the castin in any suitable manner with beneficial resu ts, but I have obtained the pipe and reagent. oreover, the artificial vent flue may be of any shape or material so long as it is capable of becommg frozen and is adapted to preserve its venting unctions during the cooling of the casting.

As my invention thus produces a dlfi'ercut and distinct type of casting, I desire to claim also, as a part of this invention, the product of my process. Fig. 1 shows a typical high carbon steel ingot cast by the present processes with its blow holes or gas pockets and its large pipe 9.

Where the thermit or like reagent is used in the pipe it is not necessary to fill the latter with the refractory bodies, but it is essential, otherwise, to employ some medium to maintain the venting functions of the pipe or vent flue.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. The hcreindescribed process for the production of solid castings, which consists in providing a vent pipe of material fusible 1n the internal heat of the castin to be vented and having one end of t e pipe closed and causing said closed end of the ing the outer portion of .Said pipe with.

'best results from the 'oint use of both vent bodies of material that will not agglomerate in the heat.

3. An ingot or like casting having incorporated in the upper portion thereof an arti-- 4. A casting having a ventingflue of a.

metal pipe filled with a reagent and penetrating below the initial chilled zone at the top of the casting.

5. The hereindescribed process for the production of solid ingots and castings, which consists in providing a vent fine of material fusible in theinternal heat of the casting, closing one end of said flue, introducing an active reagent in th closed end of the flue, charging bodies of material in the flue above the reagent of such character that they will not agglomerate in the heat of the casting, and causing the closed end of the fine to penetrate through the upper crust of the casting into its molten interior so that the closed inner, end containing the active reagent will melt away and release the reagent while its outer end containing the other material is frozen in place.

6. The hereindescribed process for the production of solid castings, which consists in providing a metal pipe with one end closed, introducing thermit into said closed end of the pipe, filling the rest of the pipe with calcareous bodies, causing said closed end of the pipe to enter into and be melted away by the molten interior of the casting while the outer end of the pipe is exposed for venting by the occluded gases, substantially as described.

7. The hereindescribed process for casting solid homogenous ingots and castings, which consists in penetrating the frozen'crust of the solidifying ingot with a vent pipe of material fusible in the casting and containing at its inner end a reagent such as thermit'whichis liberated into the molten interior of the casting when the inner end of said pipe fuses.

8. The hereindescribed process for the production of ingots and castings, which consists in introducing into the top of the ingot or casting before it hardens a fusible pipe open at its outer end and closed at its inner.

end and containing a reagent adapted to be brought into contact with the molten interior of the casting by the melting of the inner end of the pipe.

9. The hereindescribed process for the production of ingots and castings, which consists in introducing into the molten casting a fusible metal pipe closed at its inserted end and filled with a reagent, the pipe being adapted to form a venting flue which remains frozen in place in the ingot after the melting away of its inner end to charge the reagent into, the body of the ingot, and which serves to vent the gases from the molten interior of the ingot until the latter chills, substantially as described.

10. The hereindescribed casting process, which consists in introducting fluxing materials into the molten interior of the casting and maintaining by means of a pipe frozen in place in the casting a vent through the frozen outer wall of the casting to carry off the contained gases.

11. The hereindescribed process for the productionof solid castings, which consists in nniintaining a venting flue penetrating the top chilled zone of the casting and bringing into contact'with the molten interior of the casting a fluxing material to intensify the heat and increase the fluidity of the molten interior of the casting adjacent to the inner end of the vent.

In testimony whereof I afliX my signature.

JOHN B. WALKER. \Vitness:

Noam; lVELsH. 

